Scrub brush



FIG. 1 is a front right side perspective view of the scrub brush showing my new design;

FIG. 2 is a bottom plan view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a front elevation view with the back elevation view being a mirror image thereof;

FIG. 5 is a right side elevation view thereof; and,

FIG. 6 is a left side elevation view thereof. 

CLAIM The ornamental design for a scrub brush, as shown and described. 